Systems, devices and apparatuses for bony fixation and disk repair and replacement methods related thereto

ABSTRACT

The present invention features new methods, apparatuses and devices for fixing adjacent bone segments, segments of a bony structure and adjacent vertebrate of a spine. The methods, apparatuses and devices utilize a new apparatus for forming a channel in a surface of the bone or bony structure segments or adjacent vertebra or a channel submerged within the bone or bony structure segments or adjacent vertebra. In more particular embodiments such apparatuses and methods including forming an arcuate channel and which channel can receive therein a curved rod or implant member, which also preferably is arcuate, and avoids the associated problems with prior cage or straight rod and screw systems. Also featured are systems, apparatuses and methods for repairing, replacing or augmenting the nucleus and/or annulus of a disc.

This application is a divisional application of co-pending U.S. Ser. No.10/968,867 filed Oct. 18, 2004, which application claims the benefit ofU.S. Provisional Application Ser. No. 60/512,134 filed Oct. 17, 2003,the teachings of all of which are incorporated herein by reference.

FIELD OF INVENTION

The present invention generally relates to methods, systems andapparatuses for bony fixation and more particularly to methods, systemsand apparatuses adapted for fixing the bones of the spine. The presentinvention also generally relates to methods, systems and devices foraugmenting, repairing or replacing the nucleus and/or annulus of anintervertebral disk of a spine, such as the spine of a mammalian body.

BACKGROUND OF THE INVENTION

Fixation or fusion of vertebral columns with bone or material, rods orplates is a common, long practiced surgical method for treating avariety of conditions. Many of the existing procedures involve the useof components that protrude outwardly, which may contact and damage abody part, such as the aorta, the vena cava, the sympathetic nerves, thelungs, the esophagus, the intestine and the ureter. Also, manyconstructions involve components that may loosen and cause undesirableproblems, often-necessitating further surgical intervention.Additionally, limiting the success of these procedures are thebiomechanical features of the spine itself, whose structure mustsimultaneously provide support to regions of the body, protect thevertebral nervous system and permit motion in multiple planes.

As indicated above, spinal surgery for spine fusion generally involvesusing implants and instrumentation to provide support to the affectedarea of the spine while allowing the bones thereof to fuse. Thetechnology initially evolved using bone chips around and on top of anarea of the spine that had been roughened to simulate a fracture in itsconsistency. The area, having encountered the bone chips, would thenproceed to heal like a fracture, incorporating the bone chips. However,surgical procedures dealing with the spine present notable challenges.For example, bioengineers have been required to identify the variouselements of the complex motions that the spine performs, and thecomponents of the complex forces it bears. This complexity has made itdifficult to achieve adequate stability and effective healing insurgical procedures directed to the spine.

One surgical technique provided by Cloward, involves cutting a doweltype hole with a saw across or through the movable intervertebral discand replacing it with a bone graft that was harvested from the hip bone.This procedure results in a fusion of the adjacent vertebral bodies andlimits motion and mobility. However, as a result of the complex motionsof the spine, it is often difficult to secure the dowel from displacing.Further, it has become apparent over time, however, that this particulartechnique does not always yield a secure fusion.

Other techniques have been developed that involve the placement ofvarious hardware elements, including rods and hooks, rods and screws andplates and screws. The dowel technique also has advanced over the pastfive years or so, with dowels being fabricated from cadaver bone ormetals such as titanium or stainless steel. These techniques, whetherusing hardware, dowels or some combination thereof, have a common goalto enhance stability by diminishing movement, thereby resulting in orenhancing the potential of a fusion of adjacent vertebral bones. Forexample, in one of these other techniques, the disc is removed andadjacent vertebrae are positioned in a stable position by placing aplate against and traversing them, which plate is secured or anchored toeach by means of screws.

In another procedure, cages in the form of two parallel circular orrectangular devices are made out of a material such as titanium orstainless steel and these devices are fenestrated. Bone is packed in thecenter of the devices that will heal to adjacent bone through eachfenestration. In this procedure, the disc space is distracted so allligamentous structures are taut and the bones are held in their normalmaximal position of distraction. Because the cages are implanted inspongy bone, they are more likely to collapse the surrounding bone, thusresulting in loss of distraction and subsequently cage dislodgement.

U.S. Pat. No. 5,591,235 reports a certain spinal fixation device andtechnique for stabilizing vertebrae. In this technique, a hollow screwis inserted into a hole, preferably a hole saw recess, in each adjoiningvertebrae. A channel is out into the vertebrae, which is lined up withcorresponding axial slots in the screw. A rod is inserted into thechannel and so as to pass through the axial slots in the screw. The rodis secured to each of the screws by means of a locking cap. The rod alsois arranged so as to provide a bridge between the hollow screws in theadjoining vertebrae. Certain disadvantages have been surmised using sucha device and technique. For example, it has become apparent that thetrough in the vertebral bodies destabilizes some of the cortex of thevertebrae body wall, which is the strongest component.

In addition to fixation or fusion of vertebral columns, the prior artalso describes methods or other spinal repair procedures, such asdiscectomy wherein an artificial disc or prosthetic device is placedwithin the vertebrae of the spine. For such prior art methods andrelated devices, there have been short comings such as having difficultyin securing the prostheses within the vertebral space or resulting insignificant modification or damage to the load bearing surfaces of thevertebrae in an effort to secure the prosthesis.

Another method or other spinal repair technique involves augmentation ofthe nucleus of an intervertebral disk of the spine. The intervertebraldisk is a flexible cartilaginous structure that is disposed betweenadjacent vertebrae. These disks form joints between the bodies of thevertebrae, which serve to unite adjacent vertebrae and to permitmovement between them. These disks also play a role as shock absorberswhen force is transmitted along the vertebral column during standing andmovement.

Each disk is formed of two parts, a central mass called the nucleuspulpsous (herein the nucleus) and a surrounding fibrous layer, theannulus fibrosus (herein the annulus). The nucleus has a semi-gelatinousconsistency, which allows it to become deformed when pressure is placedupon it, enabling the disk to change shape as the vertebral columnmoves.

There is described in U.S. Pat. Nos. 5,047,055; 5,824,093 6,264,695; theteachings of which are incorporated herein by references, varioustechniques and/or prosthetics for use in replacing or augmenting aspinal disc nucleus. Given the structure of the disk and its locationbetween adjacent vertebrae, it is not s simple task to access thenucleus for the insertion of such prosthetics or materials to augmentthe nucleus. One technique for accessing the nucleus contemplates usingthe defect in the annulus, however, in practice the defect usually needsto be enlarged to allow the insertion of the prosthetic. Anothertechnique contemplates having the surgeon drill through one of theadjacent bodies using a lateral approach. This another technique reliesheavily on the skill and dexterity of the surgeon not to damagesurrounding tissues, nerves and blood vessels. Also, the holed formed bysuch drilling is not easily sealed because of its shape andconfiguration.

Conventional techniques relating to fixation of the spine and bonystructure rely in great part on the skill and dexterity of the surgeonto control the devices and instrumentalities being used to protectsurrounding tissues, muscles, nerves and blood vessels from damageduring the procedure. This is so because the devices and/orinstrumentalities that the surgeon uses during such techniques,themselves do not provided the surgeon with a mechanism to protect thetissues, muscles, nerves and blood vessels surrounding the treatment ortarget area within the body from coming into contact with the device orinstrumentality during the procedure. Consequently, the surgeon must usesurgical techniques to relocate tissues, muscles, nerves and bloodvessels from the surgical field, if that is possible, and for thosewhich it is not possible, the surgeon must take care in the use of thedevice or instrumentality to prevent injury. It should be recognizedthat the surgeon while inserting and retracting or removing the deviceor instrumentality from the bony structure or spine must exercise suchcare to prevent injury.

Thus, it would be desirable to provide a new apparatus, system andmethods for bony fixation that enhances healing of the bone whileproviding structural support therefore. It would be particularlydesirable to provide such an apparatus, system and method that wouldinvolve the use of open surgical or minimally invasive surgicaltechniques as well as a technique in which the implant burrows in thestructure of the bone; more particularly a technique in which theimplant burrows in the bone spine, traverses across the disk space, andends in an adjacent or neighboring vertebrae or vertebras, providinglimited or no protrusions. It also would be desirable to provide such anapparatus, system and method where the implant is retained within thebone without requiring external fixation including contour-varyingexternal vertebral wall fixation as compared to conventional devices, assuch a device would avoid many of the problems associated withconventional devices such as blood vessel injury, erosion into organs,as well as placement near nerves. It also would be desirable for suchapparatuses and systems to be adaptable for use in a wide range ofprocedures and techniques, including but not limited to augmentation ofthe nucleus such as by use of prosthetics.

SUMMARY OF THE INVENTION

The present invention features new methods, apparatuses and devices forfixing adjacent bone segments, segments of a bony structure and adjacentvertebrate of a spine. The methods, apparatuses and devices utilize anew apparatus for forming a channel in a surface of the bone or bonystructure segments or adjacent vertebra or a channel submerged withinthe bone or bony structure segments or adjacent vertebra. In moreparticular embodiments such apparatuses and methods include forming anarcuate channel. Also the channel formed can receive therein a curvedrod or implant member, which also preferably is arcuate, and avoids theassociated problems with prior cage or straight rod and screw systems.Also featured are devices used in connection with such apparatuses andmethods.

According to an aspect of the present invention there is featured amethod for forming a channel, an arcuate channel in adjacent bonesegments, adjacent segments of a bony structure or adjacent vertebra ofa spine, the bone segments, bony structure and spine more particularlybeing those of a mammalian body. Such a method includes positioning aframe assembly proximal the treatment or surgical site, securing theframe assembly to the adjacent segments of the bone or bony structure oradjacent vertebra and rotating a drill bit in fixed relation to theframe assembly to form the channel in the surface or sub-surface of thebone, bony structure or vertebra. In further embodiments, the methodfurther includes mechanically engaging a securing mechanism to the frameassembly so that the frame is maintained in fixed relation by suchmechanical engagement alone or in combination with the lateral stiffnessof the securing mechanism.

In more specific embodiments, the frame assembly includes a frame havinga plurality of through apertures, each through aperture including aconstricted portion and a plurality of securing members. Each of theplurality of securing members are driven through the through aperturesand the constricted portion and into the bone, bony structure orvertebra at the site such that the frame is secured in fixed relation tothe bone, bony segments or vertebra by the engagement of the constrictedportion with the securing member and by the lateral stiffness of thesecuring members.

In further embodiments, the method further includes attaching a drillassembly to the frame assembly so a drill bit of the drill assemblyfollows a predetermined path, more particular a predetermined circularpath, in fixed relation with respect to the frame and moving the drillbit through the predetermined path while the drill bit is rotating so asto cut the channel. In more particular embodiments, the method furtherincludes providing a pivot arm assembly having a pivot arm that rotatesin fixed relation to the frame, securing a portion of the drill assemblyincluding the drill bit to the pivot arm assembly and rotating the drillbit using the pivot arm assembly so the drill bit traverses thepredetermined path, more specifically the predetermined circular path.

Such a method further includes determining if the rotation of the drillbit in a first direction formed a complete channel or a partial channeland in the case where it is determined that a partial channel wasformed, reconfiguring the drill assembly so as to be rotatable in asecond rotational direction that is different from the first directionand rotating the drill bit in the second rotational direction to formthe complete channel.

Such methods further include locating and attaching an implant in thechannel so formed and securing the implant therein using any of a numberof techniques known to those skilled in the art. In more particularembodiments, such a method include securing the implant to the bone,bony structure or vertebra using a plurality or more of securingdevices, more specifically using a plurality of threaded members.

Also featured is a system or apparatus embodying the frame, pivot armassembly and drill assembly herein described. In addition there isfeatured devices or tools for use with such systems, apparatuses andmethods to drive the securing members or the remove the securing membersafter the channel has been formed in the surface or sub-surface of thebone, bony structure or adjacent vertebras.

In further aspects of the present invention, there are featured systems,apparatuses and methods for augmenting, repairing or replacing thenucleus and/or the annulus that embody the frame, pivot arm assembly anddrill assembly herein described as well as other such systems andapparatuses described in U.S. Pat. No. 6,607,530 and U.S. Ser. No.10/019,265 (the teachings of which are incorporated herein byreference). In such systems, apparatuses and methods, the drill isrotated as described herein to form a channel or passage through one ofthe vertebrae that is adjacent to the disk to be repaired so that thenucleus of the disk can be accessed through the vertebral end plate. Thesize of the channel or passage formed can be controlled so as to providethe desired or needed amount of access for the surgeon to insert forexample, the material or prosthetic into the nucleus as well as otherdevices or mechanisms (e.g., a patch) that can be used to form a seal orclosure at the defect on the annulus. Such control is achieved forexample, by adjusting the size of the drill bit to fit a givenapplication. Such a disk repair procedure also can include sealing ofthe channel, passage or hole formed in the vertebrae using any of anumber of techniques known to those skilled in the art, such as forexample, inserting bone or bony material into the channel.

It should be recognized that the drilling apparatus, methods and systemsof the present invention can be used anteriorally or posteriorally andso that the drill bit of such systems or apparatuses can penetrate orenter the vertebral body through the pedicles.

Other aspects and embodiments of the invention are discussed below.

BRIEF DESCRIPTION OF THE DRAWING

For a fuller understanding of the nature and desired objects of thepresent invention, reference is made to the following detaileddescription taken in conjunction with the accompanying drawing figureswherein like reference character denote corresponding parts throughoutthe several views and wherein:

FIG. 1 is a side view of a drilling apparatus according to an aspect ofthe present invention;

FIG. 2 is one perspective view of the drilling apparatus of FIG. 1;

FIG. 3 is another perspective view of the drilling apparatus of FIG. 1;

FIGS. 4A,B are various perspective views of the pivot arm assembly ofthe drilling apparatus of FIG. 1;

FIG. 5 is a perspective view of the pivot arm of the pivot arm assembly;

FIG. 6 is a perspective view of the drill assembly of the drillingapparatus and a drive motor connected thereto;

FIG. 7 is a cross-sectional side view of the drill assembly of FIG. 6;

FIG. 8 is a side view of the bit, bearing and drive cable sub-assemblyof the drill assembly;

FIG. 9 is a cross-sectional view of the drill assembly end including thebit, illustrating another exemplary bit;

FIG. 10A is a side view of a nail removal tool according to oneembodiment of the present invention;

FIG. 10B is an end view of the nail removal tool;

FIG. 11 is a perspective view of the nail removal tool mounted on theplatform assembly of the drilling apparatus;

FIG. 12 is a side view with a partial cut away of a nail drive toolaccording to an embodiment of the present invention;

FIGS. 13A-L are illustrations of the process for forming a recess inadjacent vertebral bodies;

FIGS. 14A-D are illustrations of the process for implanting or attachinga curved rod across the adjacent vertebrae;

FIGS. 15A-H are illustrations of the process for forming a throughaperture in adjacent vertebral bodies;

FIG. 15I is an illustrative view of adjacent vertebral bodiesillustrating the fixed cutting depth aspect yielded by the drillingapparatus of the present invention;

FIGS. 16A-C are illustrations of the process for implanting or attachinga curved rod in the through aperture and across the adjacent vertebrae;and

FIG. 17 is a side view of a drilling apparatus according to anotheraspect of the present invention illustrated disposed upon adjacentvertebral bodies.

FIG. 18A is a perspective view of drilling apparatus according to yetanother aspect of the present invention;

FIG. 18B is side view of the drilling apparatus of FIG. 18A;

FIG. 18C is another perspective view from a different perspective of thedrilling apparatus of FIG. 18A;

FIG. 19A is a perspective view of a portion of a spine on which ismounted a drilling apparatus of the present invention for creating achannel, passage or hole for a disk repair procedure;

FIG. 19B is a perspective view of the portion of the spine illustratingthe channel, passage or hole through an adjacent vertebrae allowingaccess to the nucleus; and

FIG. 20 is a flow diagram briefly describing a disk repair procedureaccording to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the various figures of the drawing wherein likereference characters refer to like parts, there is shown in FIGS. 1-3various views of a drilling apparatus 100 according to an aspect of thepresent invention that is generally comprised of a platform assembly200, a pivot arm assembly 300 and drill assembly 400. As hereinafterdescribed in more detail, the pivot arm assembly 300 is removablysecured to the platform assembly 200 and the platform assembly isremovably secured to the bone or bony structure so as to maintain thepivot point of the pivot arm assembly in general fixed relation to thebone or bony structure. The drill assembly 400 is removably secured tothe pivot arm assembly 300 so as to maintain the end of the drillassembly including the bit 410 or drill end in fixed relation withrespect to the pivot arm 302 of the pivot arm assembly. Consequently, asthe pivot arm 302 is rotated about the pivot point, the bit 410 followsa predetermined arcuate, curved or circular path in the bone or bonystructure as defined by the length of the pivot arm.

For purposes of illustrating the drilling apparatus 100 of the presentinvention, reference hereinafter is generally made to the structure andstructural features or elements of a mammalian spine, however, thisshall not be construed as limiting the use and application of thedrilling apparatus of the present invention to these applications. It iscontemplated and as such within the scope of the present invention toadapt the drilling apparatus of the present invention and the methodsrelated thereto so the drilling apparatus is used so as to form groovesor arcuate passages in bones or bony structures of the mammalian body inwhich grooves is received a curved rod or other member as is hereinafterdescribed thereby stabilizing and/supporting the bone or bony structure.

The platform assembly 200 includes a frame 202, a plurality of firstpath guards 204 and a mechanism for securing the frame to the bone orbony structure. In the illustrated embodiment, the securing mechanismcomprises a plurality of nail members 206 that each pass respectivelythrough each of the frame 202 and the first path guards and so as to bedisposed in the bone or bony structure as herein described. In furtherembodiments, and as hereinafter described, the platform assembly 200 canfurther include a second path guard 204 b, in cases where the drillingapparatus 100 is used to form a groove or recess in an outer surface ofthe bone or bony structure thereby providing a protective structurebetween the moving and rotating drill bit 410 and the tissues or otherstructures or features of the mammalian body (e.g., nerves, bloodvessels) that are proximal the bone or bony structure outer surface.

The frame 202 is configured and arranged so as to form an essentiallyrigid structure and frame work to which the pivot arm assembly 300 isremovable attached and at least one and more particularly two throughpassages 210 that communicate with a corresponding passage in the firstpath guards 204. The through passages 210 and the corresponding passagein the first path guards 204 are each configured and arranged so as toallow the outer tube member 402 of the drill assembly to pass therethrough as the pivot arm 302 is being rotated or pivoted about the pivotpoint. The frame 202 is composed of any one of number of materials knownto those skilled in the art that is appropriate for the intended use andthe anticipated structural loads that can be imposed during use. In anexemplary embodiment, the frame 202 is made from stainless steel such asa stainless steel bar stock.

The first path guards 204 are secured to the frame 202 so as to extenddownwardly from a bottom surface 210 b therefrom. Each of the first pathguards 204 are arranged so as to include a generally centrally locatedthrough passage, through which the outer tube member 402 and the drillbit 410 or burr of the drill assembly 400 are passed. In addition, eachof the first path guards 204 are configured and arranged so as toinclude a plurality of through passages 220, one for each of the nailmembers 206. Each of the nail member through passages 220 also arepreferably formed in the first guard member so as to present constrictedholes that firmly grab the nail member within the corresponding throughpassage. In this way, the gripping action of the through passages andthe lateral stiffness of the nail members 206 provides a mechanism forsupporting and fixing the frame 202, and in turn the pivot point'srelation with respect to the bone, bony structure or spine. In use, eachof the nail members 206 are passed through the through aperture 208 inthe frame 202 and driven through the through passage 220 of the firstpath guard 204.

In more particular embodiments, each through passage 220 is configuredand arranged so that the passages are over sized with respect to thediameter of the nail members 206 and a portion of the through passageforms a land or raised region comprising a constriction region. Moreparticularly, the constricted region is located above or from the lowerend of the through passage such that the pointed ends of each nailmember 206 are not exposed when the nail members 206 are initiallypressed into the platform assembly 200. In this way, each of the nailmembers 206 are confined within the first path guard 204 prior topositioning of the platform assembly 200 in the surgical field amidstvital structures or features of the mammalian body.

The first path guards 204 are constructed from any of a number ofmaterials known to those skilled in the art that are appropriate for theintended use and so as to provide a medium that can form a protectivebarrier between the drill path and the tissues including nerves andblood vessels that are proximal the site of the bone, bony structure orspine to be drilled. In exemplary embodiments, the first path guards 204are made form a plastic material such as, but not limited to,polycarbonate. In further embodiments, the end of the first path guard204 proximal the bone, bony structure or spine is configured andarranged so as to include a soft conformal region that contact and sealagainst the surface of the bone, bony structure or spine. Alternatively,a conformable material may be disposed in the space, if any, between thebase or bottom surface of each first path guard 204 and the opposingsurface of the bone, bony structure or spine (e.g., vertebral cortex).

The nail members 206 are configured and arranged so that each extendsfrom a top surface 210 a of the frame 200, through the frame and thefirst path guard 204 and a sufficient distance into the bone, bonystructure or spine to fix and secure the frame thereto. In addition,each of the nail members 206 also is configured and arranged so at leasta portion thereof has a diameter that is set so that this portion of thenail member is gripped within the constricted region of the throughpassage 220 of the first path guards 204 as herein described.

Each of the nail members 206 includes a head portion 230 and a shaftportion 232 one end of which is mechanically coupled to the head portionusing any of a number of techniques known to those skilled in the artthat yields a nail member that is capable of being driven into the bone,bony structure or spine and removed therefrom. In further embodiments,the nail member 206 is formed such that the head portion 230 is integralwith the shaft portion 232. In particular embodiments, the head portion230 is configured and arranged so as to allow the nail member 206 to bedriven through and into the bone, bony structure or spine and laterremoved therefrom. In further embodiments, the head portion 230 isfurther configured so as to include a through aperture or hole extendinggenerally laterally or radially through the head portion, the throughaperture being configured to receive one or more suture lines thereinfor interoperative locating.

The other end of the shaft portion 232 is configured so as to form apointed end that is appropriately configured and shaped for insertioninto the bone, bony structure or spine and for securing the pointed endand a portion of the shaft member in such bone, bony structure or spine.In illustrative embodiments, the pointed end is configured to form anon-cutting pencil point end that wedges the end into the bone, bonystructure or spine.

In the illustrated embodiment, four nail members 206 are driven througheach of the first guard members 204 and into the bone or bony structureor spine. This shall not be construed as a limitation as the number andplacement of the nail members is not so particularly limited as each endof the frame 202 can be secured to the bone or bony structure using oneor more and more particularly two or more nail members 206. It alsoshould be recognized that other mechanisms known to those skilled in theart, such as screws or threaded devices, are contemplated for use withthe present invention.

Each of the nail members 206 is composed of any one of number ofmaterials known to those skilled in the art that is appropriate for theintended use and the anticipated structural loads that can be imposedduring use. In an exemplary embodiment, the nail member 206 is made froma metal such as stainless steel.

Referring now also to FIGS. 4-5, the pivot arm assembly 300 includes aradial arm or pivot arm 302, a pivot pin bracket 304 and a pivot pin306. The pivot pin bracket 304 includes side plates 310 and finger pads312 that are secured to the side plates, where the pivot pin extendsbetween the side plates. The pivot pin 306 is received within anaperture 320 in the pivot arm such that the pivot arm can rotate about apivot axis 321.

The pivot pin bracket 304, more particularly the side plates 310thereof, is generally configured and arranged so as to secure the pivotarm assembly 300 to the platform assembly 200 so as to prevent thedisengagement of the pivot arm assembly and correspondingly the drillassembly 400 from the platform assembly when it is being rotated fromthe fully retracted position of the pivot arm. More particularly, theside plates thereof are configured and arranged such that the bracketcan be removed from the platform assembly 200 when the pivot aim is inthe fully retracted position.

In particular embodiments, the side plates 310 are configured so as toform spring members that can slide in mating grooves provided onopposing inside surfaces of the platform assembly frame 202. Inaddition, the side plates 310 further include binding head screws thatengage complimentary holes within the mating grooves to lock the pivotpin bracket 304 in place. A finger pad 312 is secured to an end of eachside plate so as to facilitate placement and removal of the pivot pinbracket 304 in the platform assembly. In illustrative embodiments, thefinger pads 312 are configured with so as to include concavities 313that the fingertips of the user can engage to thereby facilitateplacement and removal of the pivot pin bracket 304.

The pivot aim 302 is configured and arranged so an end 322 thereofincludes an aperture 320 so the pivot arm can be mounted upon the pivotpin 306 such that it can rotate or swing about the pivot pin 306. Thepivot arm 302 also is configured and arranged so as to include a matingportion 324 that receives therein and mates with a feature of the drillassembly 400 so as to removably secured the drill assembly to the pivotarm. The mating portion 324 is located distal from the end 322 of thepivot arm 302 that is mounted upon the pivot pin 306. Also, the lengthof the pivot arm 304, more particularly the distance between the pivotaxis 321 and the mating portion 324, establishes or controls the radiusof curvature of the hole or recess being formed in the bone, bonystructure or spine by the rotation of the pivot arm. It should be notedthat this radius of curvature or diameter is different from the diameterof the hole or recess formed by the rotating drill bit 410 or bur. Assuch, it is contemplated that pivot arms 302 will be provided that havelengths set that are appropriate for the given geometry and physicalmake-up of the mammalian body.

The platform assembly 200 and pivot arm assembly 300 of the presentinvention advantageously creates a mechanism that allows tissue, muscle,blood vessels (e.g., aorta) and nerves to pass under and around theplatform assembly and also to localize the drilling elements of thedrill assembly 400 within the structure of the platform assembly. Inaddition, the pivot arm assembly 300 in combination with the platformassembly provides a mechanism to control the radial movement or radialmotion of the drilling elements of the drill assembly 400 from theirinsertion into the bone or bony structure as well as the retraction fromthe bone or bony structure such that the drilling elements traverse aspecific radius of curvature during such insertion and retraction. Inthis way, the drilling apparatus of the present invention also controlsthe maximum depth within the bone or bony structure the drillingelements can attain during use. Thus, and in contrast to conventionaltechniques, devices and instrumentalities, the drilling apparatus 100 ofthe present invention provides a mechanism that protects tissues, bloodvessels and nerves from damage while the drilling elements of the drillassembly 400 are being inserted into and withdrawn from the bone or bonystructure as well as assuring that the drilling elements will follow agenerally fixed path such that the drilling elements do not come intocontact with nor damage the tissues, blood vessels and nerves proximalto and surrounding the bone or bony structure while the hole or recessis being formed in the bone or bony structure. Consequently, thedrilling apparatus 100 of the present invention minimizes the potentialfor damage without having to rely solely on the dexterity or skill ofthe surgeon, as is done with conventional techniques and devices.

In further embodiments, at least a segment or a part of the matingportion 324 is configured and arranged so as to complement the shape ofthe drive assembly feature being received therein. For example, and asillustrated, a portion or part of the key 404 of the drill assembly isconfigured so as to be polygonal in shape and the mating portion 324 isconfigured so as to include a polygonal shaped recess for receivingtherein the hexagonal surfaces of the key. Such polygonal shapesincludes but are not limited to a square, triangular, rectangular orhexagonal shapes.

In yet further embodiments, the pivot arm 302 is configured and arrangedso as to include a finger grip 326 at or proximal and end of the pivotarm that is opposite to the end 322 mounted upon the pivot pin 306. Thefinger grip 326 presents a structural element or feature that isconfigured to allow the thumb and/or fingers of the user to grasp thefinger grip so as to thereby control rotation of the pivot arm and toalso control the drilling pressure (i.e., pressure being exerted by thedrill bit 410 on the bone or bony structure while drilling the hole orrecess therein). In illustrated embodiments, the finger grip 326presents a small tab having bilateral concavities that allow the fingertips to grasp it or a through aperture.

Each of the pivot arm 302, pivot pin 306, side plates 310 and fingerpads 312 is composed of any one of number of materials known to thoseskilled in the art that is appropriate for the intended use and theanticipated structural loads that can be imposed during use. In anexemplary embodiment, any one or more of the foregoing elements of thepivot arm assembly 300 is made from a metal such as stainless steel.

Referring now also to FIGS. 6-7 there is shown a perspective view and across-sectional view of drill assembly 400 of the present invention.There also are shown in FIGS. 8-9 various views of portions or segmentsof such a drill assembly and/or embodiments thereof. The drill assembly400 generally forms a curved structure, more particularly a curvedtubular structure, that is attached to the pivot arm 302 as hereindescribed and which thus swings around the pivot point or pivot axis321. In use, the drill bit 410 rotates about its axis while this axis isheld tangent to and swept along an arc of constant radius as defined bythe distance between the mating portion 324 of the pivot arm 302 and thepivot axis 321. This movement results in or yields a toroidal hole.

The drill assembly includes an outer tube member 402, a key 404, aflexible inner housing 406, a drive cable 408, a drill bit 410 or burr,a barbed fitting 412, a drive adapter 414. In further embodiments, thedrill assembly includes a distal drive cable bearing 416 and a proximaldrive cable bearing 418. Any one of a number of motors 20 or motor driveassemblies as is known in the art having sufficient power (e.g., torque)and rotational speed are coupled to the drive adapter 414 including butnot limited to the Micro100 (Linvatech/Hall Surgical 5053-009) orBlachmax (Anspach Blackmax-KT-0). The drive adapter 414 is a swage-typeof fitting that is configured and arranged so it can be swaged upon oneend of the drive cable 408. The drive adapter 414 also is configured andarranged so as to provide an input end arrangement that can bemechanically coupled to the output end of a variety of motors or motordrive assemblies or drills including those identified herein.

The outer tube member 402 is curved to a predetermined radius ofcurvature so that the centerline thereof is a set distance from thepivot axis 321 of the pivot arm 302. The key 404 and the distal cablebearing 416 are secured to the outer tube using any of a number oftechniques known to those skilled in the art that is appropriate for thematerials comprising these elements or features. In exemplaryembodiments, the key 404 and the distal cable bearing 416 are secured tothe outer tube member by brazing or soldering. In more particularembodiments, the distal drive cable bearing 416 is secured to the outertube member 402 such that the outer edge of the outer race of thebearing lies in a radial plane from the pivot point, whereby the axis ofthe drill bit 410 or burr is arranged so as to tangent to the centerlineof the arc of the outer tube member.

The key 404 is generally cylindrical in construction and serves to alignand anchor the outer tube member 401 to the pivot arm assembly 300, moreparticularly the pivot arm 302. As indicated herein, a portion 405 ofthe key 404 is configured so as to provide a surface feature, artifactor contour that complements at least a part of the mating portion 324 ofthe pivot arm. In the illustrated embodiment, the portion 405 of the key404 forms an external polygonal feature that mates to the internalpolygonal feature provided in the pivot arm mating portion. The key 404also is configured and arranged so as to be secured to the matingportion using any of a number of techniques known to those skilled inthe art. In an exemplary embodiment, a portion of the key is configuredso as to include a external thread and a part of the mating portion 324is configured so as to include a complementary threaded element orfeature in an aperture thereof. In use, the key is articulated so as tothreadably secure or lock the key 404 to the pivot arm 302. Othertechniques for securing, such as brazing, soldering and adhesives arecontemplated for use with the present invention.

The key 404 includes a through aperture that is coupled to the innerregion or area of the outer tube member 402. The diameter of the keythrough aperture and the outer tube member are set so as to at leastallow the flexible inner housing 406 and the drive cable 408 to passthere through. The flexible inner housing 406 extends from the distalend 401 of the outer tube member 402 to the barbed fitting 412. Theflexible inner housing 406 is a generally tubular member of flexibleconstruction, such as Teflon for example, for housing the drive cable408. In particular embodiments, the flexible inner housing 406 is asmall diameter tubular member (i.e., smaller than the inner diameter ofthe outer tube member) and is secured the key 404 using any of a numberof techniques known to those skilled in the art, which are appropriatefor the materials of use. In an exemplary embodiment, the flexible innerhousing is secured to the key 404 using an adhesive, such as a medicalgrade adhesive.

The barbed fitting 412 is secured to the end of the flexible innerhousing that is opposite to the drill bit 410 using any of a number oftechniques known to those skilled in the art, which are appropriate forthe materials of use. The end of the barbed fitting 412 being secured tothe flexible inner housing 406 also is received within the flexibleinner housing. In particular embodiments, the barbed fitting 412 isconfigured and arranged so the end being received in the flexible innerhousing 406 is secured thereto by an interference fit. In furtherexemplary embodiments, the interference fit is augmented by use of anadhesive, such as a medical grade adhesive.

The proximal drive cable bearing 418 is disposed within the barbedfitting 412 in which is received the drive cable 408. In particularembodiments, the proximal drive cable bearing 418 is retained within thebarbed fitting 412 using any of a number of techniques known to thoseskilled in the art. In an exemplary embodiment, the proximal drive cablebearing is secured to the barbed fitting using one of soldering, brazingor adhesives.

The distal and proximal drive cable bearings 416, 418 are any of anumber of bearing assemblies known to those skilled in the art andappropriate for the intended use. In particular embodiments, the distaland proximal drive cable bearing 416, 418 are miniature ball bearingassemblies as is known to those skilled in the art (e.g., SR133zz MSC35380799, 0.9375″ bore, 0.1875″ OD, 0.0937″ width, double shielded).

In an alternative embodiment, the inner housing is a double curved innertube of a fixed non-flexible constriction. The double curved inner tubehas two radii of curvature, the first radius of curvature involves allbut the most distal section of the inner tube and the second radius ofcurvature involves a smaller portion of the inner tube. The secondradius of curvature is set so as to bring the path of the drive cable408 around so as to enter the proximal end of the distal drive cablebearing 416 in the correct direction. In this way, the fixed inner tubecan be configured and arranged so as to swing wide and make a turn toenter essentially parallel to the axis of an end fitting being swaged tothe end of the inner tube. In this way, fatiguing of the drive cable 408can be minimized and misalignment of the drive cable and the inner tubeproximal the end of the inner tube can be minimized.

Although specific embodiments are described herein for the outer tubemember 402 and the inner tube member or flexible inner housing 406 thisshall not be considered as particularly limiting. The present inventioncontemplates adapting the present invention using any of a number oftechniques known to those skilled in the art whereby a cable isgenerally turned through a protected series of rigid or flexiblecannulas or tubes such that a bit operably coupled to one end of thecable can turn at an end of the outer tube or cannula.

The drill bit 410 or burr is any of a number of cutting tools orimplements known to those skilled in the art and appropriate for theintended use, speed and power developed by the drive motor 20 and thematerial to be drilled. In particular illustrative embodiments, thedrill bit 410 or burr is a spade bit such as that shown in FIGS. 6-8,alternatively and with reference to FIG. 9, the drill bit is ahemispherical bit 410 a.

The drive cable 408 is a flexible cable that is more particularlycomprised of a large number of smaller strands of an appropriatematerial, including but not limited to steel, stainless steel, andtitanium, that are compound wound using any of a number of techniquesknown to those skilled in the art so as to yield a flexible cable havingthe desired width, length, flexibility and strength characteristics. Ina particularly illustrative embodiment, the drive cable 408 is a customwound 1.8 mm (0.072 in.) diameter 7×19 left regular lay strand woundcable. In more particular aspects, the drive cable 408 is manufacturedso as to be capable of being rotated or turned at a high rate of speedor revolution while maintaining its flexibility and such that right handturning of the cable should not result in the unwinding or loosening ofconstruction.

In particular embodiments, the length (“Ldc”) of the drive cable 408shall be controlled so as to maintain a relationship with the length ofthe portion of the drive cable (“Ldci”) that is disposed within theouter cannula or outer tube 402 or correspondingly the arc length of theouter tube. In more particular embodiments, the relationship between thelength of the drive cable 408 and the length of the portion of the drivecable within the outer tube 402 satisfies the following relationshipLdc≦4×Ldci; more particularly satisfies the relationship Ldc≦3×Ldci, andmore specifically satisfies the relationship Ldc≦2×Ldci. In morespecific embodiments, the length of the drive cable 408 is set based onthe particular application or material to be drilled. For example, theoverall cable length is shortened or lengthened based on the relativehardness of the material in which the channel or opening is to be formedin the bone or bony structure. In further embodiments, the flexibleinner housing 406 is configured and arranged so as to have a length thatsatisfies the foregoing relationships.

Referring now to FIG. 17 there is shown a side view of a drillingapparatus 1000 according to another aspect of the present invention thatis illustrated being disposed upon adjacent vertebral bodies. Referenceshall be made to FIGS. 1-3 and 6-9 and the discussion related theretofor features and functions not provided in the following discussion.Such a drilling apparatus 1000 includes a platform assembly 1200 and adrill assembly 1300.

The platform assembly 1200 includes a frame member 1202 and a pluralityof path guard members 1204 and a mechanism for securing the frame to thebone or bony structure. As with the drilling apparatus illustrated inFIG. 1, the securing mechanism comprises a plurality of nail members 206that each pass respectively through each of the path guard members 1204so as to be disposed in the bone or bony structure as herein described.In further embodiments, and as hereinafter described, the platformassembly 1200 can further include a second path guard 205, in caseswhere the drilling apparatus 1000 is used to form a groove or recess inan outer surface of the bone or bony structure thereby providing aprotective structure between the moving and rotating drill bit 410 andthe tissues or other structures or features of the mammalian body (e.g.,nerves, blood vessels) that are proximal the bone or bony structureouter surface.

The frame member 1202 and the first guard members 1204 are configuredand arranged so as to form an essentially rigid structure and frame workto which the drill assembly 1300 is removable attached and at least oneand more particularly two through passages 1205. Each of the throughpassages 1205 are configured and arranged so as to allow the outer tubemember 402 of the drill assembly 1300 to pass there through as drill bit410 is being is being rotated or pivoted about the pivot point. Theframe member 1202 is composed of any one of number of materials known tothose skilled in the art that is appropriate for the intended use andthe anticipated structural loads that can be imposed during use. In anexemplary embodiment, the frame member 1202 is made from stainless steelsuch as a stainless steel bar stock.

The first path guard members 1204 are secured to the frame member 1202using any of a number of techniques known to those skilled in the art sothat the through aperture 1205 extends downwardly towards a bottomsurface thereof. As indicated above, the though passage 1205 in each ofthe first path guard members 1204 are arranged so the outer tube member402 and the drill bit 410 or burr of the drill assembly 1300 are passedthere through. In addition, each of the first path guard members 1204are configured and arranged so as to include a plurality of throughpassages, one for each of the nail members. Reference shall be made tothe foregoing discussion for the nail member through passages 220 ofFIG. 1 for further detail and characteristics of these nail memberthrough apertures.

The frame member 1202 also is configured and arranged so as to provide amechanism for guiding the drill assembly 1300 such that the drill bit410 thereof follows a predetermined arc or radius of rotation. Inillustrative embodiments, the frame member 1202 is configured so as toinclude a web portion 1210 that extends width wise along thecircumferential length of the frame member. In further embodiments, theframe member 1202 is configured and arranged so as to form a step regionor a discontinuous radial region 1212 at the ends of the frame memberproximal the first guard members 1204 so as to form in effect a radialstop.

The drill assembly 1300 generally forms a curved structure, moreparticularly a curved tubular structure, that is coupled to the framemember 1202 as herein described and which thus swings around a pivotpoint or pivot axis that is defined by the frame member 1202. In use,the drill bit 410 rotates about its axis while this axis is held tangentto and swept along an arc of constant radius as defined by the pivotpint. This movement results in or yields a toroidal hole in the bone orbony structure.

The drill assembly includes an outer tube member 402, a key 404, aflexible inner housing 406, a drive cable 408, a drill bit 410 or burr,a barbed fitting 412, a drive adapter 414 and movable mount member 1310.In further embodiments, the drill assembly includes a distal drive cablebearing 416 and a proximal drive cable bearing 418. As indicated abovereference shall be made to FIGS. 1-3 and 6-9 for details andcharacteristics of the drill assembly 1000 not otherwise shown in FIG.17 or described hereinafter.

The movable mount member 1310 includes a frame member mounting portion1312 and a drill assembly mating portion 1314 that form an integralstructure. The frame member mounting portion 1312 is configured andarranged so as to be slidably mounted upon the frame member 1202, morespecifically the web portion 1210 thereof. Thus, motion of the framemember mounting portion 1312 along the circumference of the frame member1202 causes the drill bit 410 to in effect rotate about a fixed point,the pivot point defined by the arcuate portion of the frame member.

As with the mating portion 324 of the pivot arm 302, the drill assemblymember mating portion 1314 is configured and arranged so as to receivetherein the drill assembly key 404. Reference shall be made to thediscussion herein for the pivot arm mating portion 324 and the drillassembly key 404 for further details and characteristics of the drillassembly mating portion 1314.

In further embodiments, the movable mount member 1310 is configured andarranged so as to include a finger grip 1316 at or proximal an end ofthe mount member 1310 that is opposite to the end frame member 1302. Thefinger grip 1316 presents a structural element or feature that isconfigured to allow the thumb and/or fingers of the user to grasp thefinger grip so as to thereby control movement of the movable mountmember 1310, rotation of the drill bit 410 and to also control thedrilling pressure (i.e., pressure being exerted by the drill bit 410 onthe bone or bony structure while drilling the hole or recess therein. Inillustrated embodiments, the finger grip 1316 presents a small tabhaving bilateral concavities that allow the finger tips to grasp it or athrough aperture.

In an alternative embodiment, the frame member 1202 is configured andarranged so as to comprise two sub-members being spaced from each other.The two sub-members further include a slot or other feature in opposingsurfaces of the sub-members, which slot or other feature extends in thecircumferential direction. In this embodiment, the frame mountingportion 1312 of the movable mount member 1310 is configured and arrangedso as to be received in and slide within the slot in each of theopposing surfaces. In this way, the drill bit 410 can be rotated about afixed point defined by the circumferentially arranged slots in the twosub-members. The foregoing is illustrative of a couple of techniques forconfiguring the frame member 1302 and the frame member mount portion1312 so the drill bit 410 can be rotated about a fixed point beingdefined by the structure of the frame member, however, the foregoingshall not be considered limiting as it is within the scope of thepresent invention to adapt the drilling apparatus of the presentinventions so as to provide a mechanism by which the drill bit can berotated about a fixed point and/or such that the drill bit follows afixed path during the drilling process.

Referring now to FIGS. 18A-C there are shown various views of a drillingapparatus 100 a according to yet another aspect of the present inventionthat is generally comprised of a platform assembly 200, a pivot armassembly 300 a and a drill assembly 400 a. Reference shall be made toFIGS. 1-9 and the discussion related thereto for features and functionsin common with the above-described drilling apparatus 100 shown thereonand not more particularly provided in the following discussion or shownin FIGS. 18A-C. Reference also shall be made to FIGS. 1-9 and thediscussion related thereto for details concerning the removablyattachment of the pivot arm 300 a to the platform assembly 200 and theremovable securing of the platform assembly 200 to the bone or bonystructure.

The pivot arm assembly 302 a includes a radial arm or pivot arm 302 a, apivot pin bracket 304 and a pivot pin 306. The pivot pin bracket 304includes side plates 310 and finger pads 312 that are secured to theside plates, where the pivot pin extends between the side plates. Thepivot pin 306 is received within an aperture 320 in the pivot arm 302 asuch that the pivot arm can rotate about a pivot axis 321. The pivot arm302 a is configure and arranged so as to include a mating portion 324 athat is distal from the end 322 of the pivot arm that is mounted uponthe pivot pin. In further embodiments, the pivot arm includes a fingergrip 326 a. Reference shall be made to the foregoing discussion forFIGS. 1-9 for further details of the pivot pin bracket 304, the pivotpin 306, and certain features of the pivot arm 302 a not describedfurther below. Reference also shall be made to the discussion above forthe pivot arm 302 and the finger grip 326 for further details regardingthe construction other characteristics for the pivot arm 302 a andfinger grip 326 features not expressly described below or shown in FIGS.18A-C.

The drill assembly includes a curved or arcuate member 452, a drivecable 456, a drill bit 410 or burr, a drive adapter 414 and a distaldrive cable bearing 416. Reference shall be made to the foregoingdiscussion for FIGS. 1-9 for further details of the drill bit 410, thedrive adapter 414 and the distal drive cable bearing 416 not otherwiseprovided below or shown on FIGS. 18A-C. Reference also shall be made tothe discussion above for the drive cable 408 for further detailsregarding the construction, width and other features not expresslydescribed below.

As indicated herein any one of a number of motors 20 or motor driveassemblies as is known in the art having sufficient power (e.g., torque)and rotational speed are coupled to the drive adapter 414 including butnot limited to the Micro100 (Linvatech/Hall Surgical 5053-009) orBlachmax (Anspach Blackmax-KT-0). The drive adapter 414 is a swage-typeof fitting that is configured and arranged so it can be swaged upon oneend of the drive cable 456. The drive adapter 414 also is configured andarranged so as to provide an input end arrangement that can bemechanically coupled to the output end of a variety of motors or motordrive assemblies or drills including those identified herein.

The pivot arm mating portion 324 a is secured to a portion of the drillassembly curved or arcuate member 452 using any of a number oftechniques known to those skilled in the art that are appropriate forthe use and materials used in the construction of these features. In aspecific embodiment, the arcuate member 452 is removably secured to thepivot arm-mating portion 324 a (e.g., mechanical fasteners, adhesives)and in other embodiment the arcuate member is secured to the pivotarm-mating portion (e.g., adhesives, soldering, brazing) so as to forman integral structure. In further embodiments, at least a segment orportion of the pivot arm-mating portion 324 a is configured and arrangedso as to complement the shape of the portion of the arcuate member 452being received therein. For example and as illustrated in FIGS. 18A-B,the arcuate member 324 also has a curved or arcuate cross-section. Thus,the pivot arm mating portion 324 a is configured so as to receivetherein a curved member having a curved or arcuate cross section. Thisshall not be considered limiting as the arcuate member 452 can beconfigured and arranged so as to have any of a number of externalcross-sectional shapes.

As indicated above, the arcuate member 452 forms a curved structure thatis attached to the pivot arm 302 a as herein described and which thusswings around the pivot point or pivot axis 321. In use, the drill bit410 rotates about its axis while this axis is held tangent to and sweptalong an arc of constant radius as defined by the distance between themating portion 324 a of the pivot arm 302 a and the pivot axis 321. Thismovement results in or yields a toroidal hole.

The arcuate member 452 is curved to a predetermined radius of curvatureso that the centerline thereof is a set distance from the pivot axis 321of the pivot arm 302 a. In further embodiments, the arcuate member 452is a tubular like member having a portion of the tubular structureremoved so the arcuate member 452 includes a dished area or depressedregion 453 in which is received the drive cable 456 as hereinafterdescribed. In an illustrative embodiment, the dished area or depressedregion 453 is generally curved or circular in cross-section as moreclearly illustrated in FIGS. 18A, C. This, however, shall not belimiting as other geometric shapes are within the scope of the presentinvention that do not unduly impair the rotational capability of thedrive cable 456 when received in the depressed region 453. In furtherembodiments, the dished area or depressed region 453 of the arcuatemember 452 is sized and arranged so as to be capable of removablyreceiving therein the drive cable 456 and, more particularly so externalsurfaces of the drive cable are within an envelope or boundary definedby the depressed region 453 of the arcuate member.

The distal end 451 of the arcuate member 452 provides a structure inwhich the distal distal cable bearing 416 can be secured therein usingany of a number of techniques known to those skilled in the art that isappropriate for the materials comprising these elements or features. Inexemplary embodiments, the distal cable bearing 416 is secured withinthe arcuate member distal end 451 by brazing or soldering. Such astructure also provides a fixed point of attachment for the drive cable456 such that that end of the drive cable and the drill bit 410 moveswith the rotation of the arcuate member about the pivot axis 321. Inmore particular embodiments, the distal drive cable bearing 416 issecured within the arcuate member 452 such that the outer edge of theouter race of the bearing lies in a radial plane from the pivot point,whereby the axis of the drill bit 410 or burr is arranged so as to betangent to the centerline of the arc of the arcuate member.

When drilling of an aperture or hole in the bone or bony structure isdesired, the surgeon or medical personnel applies a force to the fingerportion 326 a so as to cause the arcuate member 452 to rotate about thepivot axis 321 and so as to cause the distal end 451 of the arcuatemember to also rotate about the pivot axis. As the arcuate member distalend 451 rotates through the platform assembly 200, the drive cable 456also is drawn along with the distal end and also is received in thedepressed region 453 of the arcuate member (e.g., as the cable passesbelow the platform assembly 200). In this way, the rotating drive cable456 is caused to lie within the depressed region 453 while the drivecable 456 is disposed within the bone or bony structure as the channelor aperture is being formed in the bone or bony structure as hereinafterdescribed.

The arcuate member 452 according to this aspect of the present inventionminimizes stress on the drive cable and reduces the amount of accessrequired by the surgeon to perform the surgical procedure. Thearrangement, however, also yields an apparatus that advantageouslycreates a mechanism that allows tissue, muscle, blood vessels (e.g.,aorta) and nerves to pass under and around the platform assembly 200 andalso to localize the drilling elements of the drill assembly 400 awithin the structure of the platform assembly. In addition, the pivotarm assembly 300 a in combination with the platform assembly 200provides a mechanism to control the radial movement radius or motion ofthe drilling elements of the drill assembly 400 a from their insertioninto the bone or bony structure as well as the retraction from the boneor bony structure such that the drilling elements traverse a specificradius of curvature during such insertion and retraction. In this way,the drilling apparatus 100 a according to this aspect of the presentinvention also controls the maximum depth within the bone or bonystructure the drilling elements can attain during use. Thus, and incontrast to conventional techniques, devices and instrumentalities, thedrilling apparatus 100 a of the present invention provides a mechanismthat protects tissues, blood vessels and nerves from damage while thedrilling elements of the drill assembly 400 a are being inserted intoand withdrawn from the bone or bony structure as well as assuring thatthe drilling elements will follow a generally fixed path such that thedrilling elements do not come into contact with nor damage the tissues,blood vessels and nerves proximal to and surrounding the bone or bonystructure while the hole or recess is being formed in the bone or bonystructure. Consequently, the drilling apparatus 100 a of the presentinvention minimizes the potential for damage without having to relysolely on the dexterity or skill of the surgeon as is done withconventional techniques and devices.

Upon completion of the procedure involving use of the drill assembly 100of the present invention, and as described herein, the nail members 206are acted upon so as to remove each of the nail members from the bone orbony structure or spine. This removal can be accomplished using any of anumber of techniques or devices known those skilled in the art. Inparticular embodiments of the present invention, and with reference toFIGS. 10A,B, there is shown a side view and an end view respectively ofa nail member removal device 500 according to the present invention.Reference also should be made to FIG. 11, which illustrates the removaltechnique using such a nail member removal device 500.

The nail member removal device 500 includes a block member 502 and aknurled screw member 506. The block member 502 includes a throughpassage that extends lengthwise in the block member so as to form asaddle structure that can straddle and slide along side rails 203 of theframe 202. In further embodiments, the block member 502 includes aslotted passage 512 that extends from a bottom surface to a top surfaceof the block member and extends partially lengthwise to a surface of thethrough aperture 504 or hole that is formed in the block member. Theslotted passage 512 also is generally sized so to allow the block memberto slide past the head portion 230 that is sticking up above the topsurface 210 a of the frame, more particularly the side rails thereof.

The threaded aperture 504 or hole is positioned within the block member502 so that it can be centered over one of the head portions 230 of thenail members 206. In use, the nail members 206 are typically driven intothe bone or bony structure such that a bottom surface of the headportion 230 is proud of or above the frame top surface 210 a. As such alower portion of the knurled screw member 506 is machined so as toinclude a side pocket 514 therein. The side pocket 514 is made in thescrew member 506 so as to have sufficient depth (e.g., width) and lengthto accommodate the head portion coaxially therein. The bottom segment ofthe screw member 506 also includes a notch that extends generallyradially to allow the nail member shaft portion 232 to be receivedtherein and so as to be also coaxial with the screw member.

In particular embodiments, when the screw member 506 is rotated in onedirection (e.g., clockwise) the side pocket 514 can be aligned with theslotted through passage 512 and thus be ready to receive therein a nailmember head portion 230. The block member 502 is slide along the frameside rail 203 until the head portion is contained within the side pocket514. After the head portion is disposed in the side pocket, the screw isrotated in the opposite direction (e.g., counterclockwise) therebycausing the screw to rotate in an upwardly direction drawing the notchedbottom surface of the side pocket into contact with the bottom surfaceof the head portion. When the notched bottom surface of the side pocket514 engages the bottom surface of the head portion, continued rotationof the screw member 506 also causes the head portion to be movedupwardly. In this way, the pointed end of the shaft portion is withdrawnfrom the bone or bony structure.

In more particular embodiments, the block member 502 and the slottedpassage 512 therein are formed such that a portion of the block memberis disposed over an end portion of the end rail of the flame 203. Thisestablishes a configuration whereby the pulling load is applied betweentwo support points, thereby minimizing the potential for tipping of thenail member removal device 500 due to unbalanced force couples.

As indicated herein, prior to use of the drilling capabilities of thedrilling assembly 100 of the present invention, the nail members aredriven into contact with the constricted regions of the first pathguards 204 and into engagement with the bone or bony structure or spine.This driving of the nail members can be accomplished using any of anumber of techniques or devices known those skilled in the art. Inparticular embodiments of the present invention, and with reference toFIG. 12 there is shown a side view with a partial cut-away of a nailmember drive tool 600 according to the present invention.

The drive tool 600 is a generally cylindrical member having a blind hole602 or aperture in one end thereof. The blind hole 602 is sized so as toreceive therein a head portion 230 of a nail member 206. The drive tool600 is constructed so that an impact load, such as that imparted by ahammer, at the opposite end 604 thereof drives the nail member 206disposed in the blind hole 602. In further embodiments, the blind hole602 also is sized so as to generally prevent the tool from slipping offthe head portion. In yet further embodiments, the depth of the blindhole 602 is set so that the bottom surface of the head portion 230remains a predetermined distance above the frame top surface 210 a so asto allow the head portion to be later received in the side pocket of thescrew member 506 of the nail member removal device 500.

As indicated herein the drilling apparatus 100 of the present inventionis adaptable for use for forming recesses or holes in bones, bonystructures or the spine of a mammalian body. The following describes theuse of the drilling apparatus in connection with two differenttechniques (i.e., anterior approach and medial approach) for forming arecess or an aperture in adjacent vertebral bodies of a spine. Althoughthe following discussion specifically refers to the drilling apparatus100 shown in FIG. 1 it shall be understood that the below describedtechniques can be used in conjunction with the drilling apparatus 1000,100 a shown in FIGS. 17-18 as well as other embodiments of suchapparatuses 100, 100 a, 1000. Referring now to FIGS. 13A-L there isshown a series of views illustrating the process for the anteriorapproach. Reference shall also be made to FIGS. 1-11 and 17-18 and thediscussion related thereto for features and functions not provided inthe following discussion.

The area of concern is exposed by a surgeon using one of atransperitoneal or retroperitoneal approach, as shown in FIG. 13A and adiscetomy is performed at the level to be instrumented and immobilized.After placing a support (e.g., a femoral ring allograft) in the discspace, lateral stabilization is performed (see FIG. 13B).

The drilling apparatus frame 202 is aligned such that it is vertical inan anteroposterior orientation and placed as far lateral as possible onthe anterolateral aspect of the vertebrae across the operative level.Temporary placement pins 700 are driven into the vertebral cortex tohold the frame 202 in place while creating the channel or recess. Inaddition, the present invention contemplates the addition of a secondpath guard 204 b that extends between the first path guards 204. Thesecond path guard 204 b is arcuate or curved having a radius thatgenerally corresponds to the path of the drill bit 410. The second pathguide 204 b also is configured so as to extend outwardly from thevertebral cortex so as to provide a barrier between the drill bit travelpath and tissues, nerves and blood vessels proximal the site. The secondpath guard 204 b is constructed of similar materials as the first pathguards 204. See FIGS. 13D-E.

When the frame 202 is positioned in the intended fashion, the pivot armassembly 300 is located and secured within the frame 202, thereby alsosecuring the drill assembly 200 in the frame. See FIG. 13E. The drivemotor 20 or drive motor assembly is then secured to the adapter 414. Thepivot arm 302 is then positioned so the drill assembly/drill bit is inthe starting position so the channel or recess can be cut. See FIG. 13F.

The drill motor 20 is started so as to cause the drill bit 410 to rotateat the desired speed and power, and the pivot arm 302 is rotated aboutthe pivot point thereby causing the drill bit 410 to rotate in apredetermined direction in a downward, circular path as dictated by theframe and the pivot arm. The resulting cut should be made immediatelyadjacent to the lateral vertebral surface. This cut is complete when thedrill bit 410 reaches the disc space as shown in FIG. 13G.

Once the first half of the channel is cut, and with the drive motor 20turned off and/or disconnected from the adapter 414, the pivot arm isrotated in the opposite direction to return it to the starting position,where the pivot arm assembly 300 can be removed from the frame 202.After removing the pivot arm assembly 300 from the frame 202, the pivotaim assembly is flipped to the opposites side of the frame andreconnected to the frame. In this way, a matching channel can be cutinto the other vertebra adjacent to the operative level. See FIG. 13H.As with the first cut, the drive motor 20 is turned on and the pivot armrotated so the drill bit 410 follows a downward, circular path. Afterthe second half of the channel has been cut, the pivot arm is returnedto the starting position and the pivot arm assembly 300 is removed fromthe frame 202. See FIGS. 13I-J.

The temporary placement pins 700 are removed from the vertebral bodiesand the frame 202 is removed from the operative site (see FIG. 13K) anda standard osteotome chisel can be used to remove any remaining bonefrom the channel edges so that the channel is open to receive or acceptthe curved rod.

Now with reference with FIGS. 14A-D there is shown the process forplacing, positioning and attaching or implanting a curved rod 800,including those described in any of U.S. Pat. No. 6,607,530 and U.S.Ser. No. 10/019,265, the teachings of which are incorporated herein byreference. The curved rod 800 is positioned in the channel and securedto the vertebral bodies using interlocking screws 802, 804 that traversethe rod and penetrate the vertebra at an angle that will avoid sensitiveneurologic structures. The screws hold the curved rod 800 in place andstabilize the motion segment to facilitate healing of the bone withinthe disc space.

Two lateral screws 802 pass through the lateral holes of the curved rodand set on the lateral surface of the implant. The two end screws 804are passed through the open ends of the curved rod and each is inserteduntil the screw head is contained within the hollow of the implant. Thelateral and end screws are inserted using for example a Cardanscrewdriver 806. As shown in FIGS. 14C-D the curved rod is now securelyin place in either of the recess (FIG. 14C) or a surface-mountedconfiguration (FIG. 14D).

Referring now to FIGS. 15A-H there is shown a series of viewsillustrating the process for the medial approach. Reference shall alsobe made to FIGS. 1-11 and 17-18 and the discussion related thereto aswell as for FIGS. 13-14 for features and functions not provided in thefollowing discussion. As above, the area of concern is exposed by asurgeon using the appropriate technique and the drilling apparatus frame202 is aligned such that it is vertical in an anteroposteriororientation and placed as far midline as possible on the anterior aspectof the vertebrae across the operative level. The pointed ends of thenail members 206 are then driven through the platform frame 202 and thefirst path guards 204 so as to be driven into the vertegral cortex tohold the frame in place while cutting the channel or through aperture.See FIG. 15A-B.

The pivot arm assembly 300 is then secured to the frame 202 and therebyalso securing the drill assembly to the frame. The drive motor 20 alsois coupled to the drill assembly 300 via the adapter 414 See FIG. 15C.The pivot arm 302 is then rotated until the drill bit 410 and the pivotarm are in the start position, whereat the drill motor 20 is started.See FIG. 15D. The pivot arm is rotated so as to cause the drill bit totravel in a downward circular path thereby making cuts in the vertebralbody. In the case where, the first cut does not cut a complete channelor through aperture, the pivot arm assembly is detached from the frame,flipped, reconnected to the frame and the cutting process describedabove is repeated until the rest of the channel or through aperture hasbeen cut. See FIGS. 15D-F.

There is shown in FIG. 15I, a illustrative view of adjacent vertebralbodies with the drilling apparatus 100 of the present invention mountedthereon. As illustrated, the arrangement of the drilling apparatus 100of the present invention is such that the drilling bit follows a fixedpath established by the configuration of the drilling apparatus 100. Inthis way, a maximum or fixed cutting depth also is set or established bythe configuration of the drilling apparatus 100.

After the complete channel or through aperture is cut in the adjacentvertebral bodies, the pivot arm assembly 300 and the drill assembly 400are detached from the frame 202 and the nail members 206 are removedfrom the vertebral bodies and the frame or platform assembly 200 isremoved from the operative site. As indicated herein, removal of thenail members 206 can be accomplished using the nail member removaldevice 500 of the present invention. The above process yields a channelopening or through aperture in both vertebral bodies that can accept thecurved rod 800. See FIGS. 15G-H.

It should be recognized that it is within the scope of the presentinvention to cut a channel through or partially through one of thevertebral bodies. Thus, the foregoing process is adaptable foraccomplishing this by limiting rotational movement such that a channelis not cut completely through one of the vertebral bodies.

Now with reference to FIGS. 16A-C there is shown the process forplacing, positioning and attaching or implanting a curved rod 800,including those described in any of U.S. Pat. No. 6,607,530 and U.S.Ser. No. 10/019,265, the teachings of which are incorporated herein byreference. The curved rod 800 is inserted into the channel andmanipulated so that the curved rod is submerged along the midline of thevertebra (see FIGS. 16A-B). The curved rod 800 is now secured to thevertebral bodies using interlocking screws 804 that traverse the rod andpenetrate the vertebra at an angle that will avoid sensitive neurologicstructures. The screws hold the curved rod 800 in place and stabilizethe motion segment to facilitate healing of the bone within the discspace.

Two end screws 804 are passed through the open ends of the curved rodand each is inserted until the screw head is contained within the hollowof the implant. The screws are inserted using for example a Cardanscrewdriver 806.

It should be recognized, and as taught in any of U.S. Pat. No. 6,607,530and U.S. Ser. No. 10/019,265, the teachings of which are incorporatedherein by reference, the curved rods 800 can be configured so as toinclude fenestration or surface artifacts that secure the curved rodwithin the channel without the retaining screws 804 are described aboveor in addition to such retaining screws.

As indicated herein, the drilling apparatus of the present invention isadaptable for use in a wide range of spinal repair procedures includingbut not limited to a repair procedure for an intervertebral disk 5 (FIG.19A,B). Although the following discussion refers to the drillingapparatus 100 according to one aspect/embodiment of the presentinvention, it is contemplated that any of the drilling apparatusesherein described are adaptable for use to perform such a disk repairprocedure. Also, it is contemplated that a disk repair procedureaccording to the present invention also can be accomplished using any ofthe devices, apparatuses or mechanisms described in and as taught in anyof U.S. Pat. No. 6,607,530 and U.S. Ser. No. 10/019,265.

Referring now to FIGS. 19A-B, there is shown a drilling apparatus 100mounted/secured upon a spine, more specifically adjacent vertebrae 2,Step 2000. Such mounting and securing is accomplished using the methodsand techniques for doing so as described herein. Reference shall be madeto FIGS. 1-9 and the discussion related thereto, for further details ofthe drilling apparatus not provided below. Reference also should be madeto the process flow diagram illustrated in FIG. 20.

In further embodiments, the drill bit 410 of the drilling apparatus 100and related components are selected so that the channel, passage or hole3 in the adjacent vertebrae 2 is sized so as to provide a desired accessto the nucleus for carrying out the repair procedure. For example, thehole 3 may be one size if a fluid or gel is to be injected into thenucleus, whereas it may be made larger if a prosthetic or device is tobe inserted through the hole so as to reside in the area within theannulus for the disk nucleus.

After the drilling apparatus 100 is so mounted, the surgeon wouldmanipulate the drill bit so as to cause it to rotate and create a curvedor arcuate hole 3 in the adjacent vertebrae and into the disk 5, Step2002. Such a drilling operation advantageously minimizes penetration ofthe vertebral endplates. Also, the drill as it follows the predeterminedcurved or arcuate path penetrates the vertebral end plates atessentially a right angle, thereby creating a circular defect. Incontrast, the straight drill used in conventional techniques wouldpenetrate the end plate at an angle thereby causing a larger ellipticalshaped defect. The near perpendicular access created by the drillingapparatus of the present invention also minimizes trauma and/ordisruption to the natural nucleus material. In contrast, a straightdrill would need to penetrate more deeply into the disc space tocomplete the access hole.

In this regard it should be noted that while it is desirous to penetratethe nucleus of the disk, it should be recognized that it is possiblethat a portion of the annulus also may be drilled during the drillingprocedure. Such an occurrence, however, shall not be construed as beingunacceptable or outside the scope of the present invention.

Following creating of the hole, the drill bit 410 is extracted orremoved from the hole 3 thereby allowing the surgeon access to the holeand thus the nucleus of the disk to be repaired. In particularembodiments, the surgeon would remove the drilling apparatus 100 so asto provide clear access to the opening formed by the hole 3, Step 2004.Thereafter, the surgeon would perform the particulars of the diskrepair/replacing/augmentation procedure, such as but not limited toremoving nucleus material (Step 2006), delivery of the nucleusaugmentation material, artificial disk and/or artificial nucleus (Step2008) and plugging of the channel, passage or hole 3 made in theadjacent vertebrae 2 (Step 2010). The nucleus material can be removedusing any of a number of techniques known to those skilled in the artincluding but not limited to water jets, chemical agents such asChymopapain chemonucleolysis, rongers and emulsification technology.

Such augmentation material includes but is not limited to the devices,mechanisms and materials described in U.S. Pat. No. 5,824,093, U.S. Pat.No. 6,264,695 and U.S. Pat. No. 5,047,055 the teachings of which areherein incorporated by reference. Also, such delivery of the nucleusaugmentation material, as well as such repair procedures, can includedelivery and positioning of an annulus closure mechanism or device toseal or retain the artificial disc, nucleus and/or nucleus augmentationmaterial or provide a closure for a defect in the annulus (such as butno limited to the devices described in U.S. Pat. Nos. 6,425,919 and6,593,625, the teaching of which are incorporated herein by reference).As is known to those skilled in the art, when the annulus becomesdamaged a defect is formed in the annulus that allows the nucleus forexample, to cause the disk to bulge in a given direction. In addition,to delivery of nucleus or annulus repair and augmentation materials, italso is contemplated that drugs, medicaments, or other treatmentmaterials can be delivered to the disk 5, vertebrae 2 or other elementof the body.

The plugging of the hole 3 is accomplished using any of a number oftechniques known to those skilled in the art, including but not limitedto the use of bone/bone graft material. It also is contemplated that anarcuate rod as herein described also can be used to plug the hole 3.Thus, the plugging of the hole 3 becomes a relatively straightforwardprocedure. Also, the plugging should advantageously create a relativelysmooth surface at the end plate and the load forces on the vertebral endplate will be perpendicular to the access hole. Such plugging isparticularly advantageous as compared to some conventional techniques asdefects in the annulus do not heal; whereas defects in the bone (e.g.,the vertebral body) can be plugged with bone, metal, etc. and the boneheals around the plug.

It should be recognized that the drilling apparatus, methods and systemsof the present invention can be used anteriorally or posteriorally andso that the drill bit of such systems or apparatuses can penetrate orenter the vertebral body through the pedicles.

Although a preferred embodiment of the invention has been describedusing specific terms, such description is for illustrative purposesonly, and it is to be understood that changes and variations may be madewithout departing from the spirit or scope of the following claims.

INCORPORATION BY REFERENCE

All patents, published patent applications, US patent application andother references disclosed herein are hereby expressly incorporated byreference in their entireties by reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents of the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

What is claimed is:
 1. A method for forming a channel in one or moresegments of a bone, bony structure or adjacent vertebrae of a spine,said method comprising the steps of: positioning a frame assemblyproximal a treatment or surgical site, securing the frame assembly toadjacent segments of the bone or bony structure or adjacent vertebrae;providing a pivot arm that rotates in fixed relation to the frameassembly, the pivot arm being removably coupled to the frame assembly;operably coupling a drill bit to the pivot arm so the drill bit followsa predetermined path in fixed relation with respect to the frameassembly as the pivot arm is rotated; rotating the drill bit in fixedrelation to the frame assembly to form a first channel in a surface orsub-surface of the bone, bony structure or vertebrae, detaching thepivot arm from the frame assembly; reattaching the pivot arm to theframe assembly; and forming a second channel adjacent to and connectingwith the first channel.
 2. The method of claim 1, wherein said securingfurther includes mechanically engaging a securing mechanism to the frameassembly and to the adjacent segments of the bone or bony structure oradjacent vertebrae, wherein the frame assembly is maintained in fixedrelation by such mechanical engagement.
 3. The method of claim 2,wherein the frame assembly is maintained in fixed relation by suchmechanical engagement and lateral stiffness of the securing mechanism.4. The method of claim 2, wherein the frame assembly being providedfurther includes a frame having a plurality of through apertures, eachthrough aperture including a constricted portion and a plurality ofsecuring members and wherein said securing further includes: drivingeach of the plurality of securing members through the through aperturesand the constricted portion and into the bone, bony structure orvertebrae at the site, whereby the frame is secured in fixed relation tothe bone, bony segments or vertebrae by the engagement of theconstricted portion with the securing member.
 5. The method of claim 4,wherein the frame is secured in fixed relation by lateral stiffness ofthe securing members.
 6. The method of claim 1, further comprising:providing a drill assembly including the drill bit; attaching the drillassembly to the pivot arm so the drill bit follows the predeterminedpath in fixed relation with respect to the frame assembly; and movingthe drill bit through the predetermined path while the drill bit isrotating thereby cutting the first channel with the drill bit, wherein alength of the pivot arm establishes a radius of curvature of the firstchannel being formed.
 7. The method of claim 1, further comprising thestep of rotating the drill bit while rotating the pivot arm therebycutting the first channel with the drill bit.
 8. The method of claim 7,wherein the step of rotating the drill bit includes moving the pivot armand drill bit in a first direction to form the first channel, whereinthe step of forming a second channel comprises moving the pivot arm anddrill bit in a second direction that is different from the firstdirection to form the second channel; and wherein the steps of detachingand reattaching allow the pivot arm to be rotatable in the seconddirection.
 9. The method of claim 1, wherein the step of rotating thedrill bit includes moving the pivot arm and drill bit in a firstdirection to form the first channel, wherein the step of forming asecond channel comprises moving the pivot arm and drill bit in a seconddirection that is different from the first direction to form the secondchannel; and wherein the steps of detaching and reattaching allow thepivot arm to be moveable in the second direction.
 10. The method ofclaim 1, further comprising the steps of: locating an implant in thefirst and second channels; and attaching the implant within the firstand second channels to the bone, bony structure or vertebrae.
 11. Themethod of claim 10, wherein said attaching includes securing the implantto the bone, bony structure or vertebrae using a plurality of securingdevices.
 12. A method for gaining access to an intervertebral discspace, said method comprising the steps of: positioning a frame assemblyproximal a treatment or surgical site; securing the frame assembly toadjacent segments of a bone or bony structure or adjacent vertebrae;providing a pivot arm that rotates in fixed relation to the frameassembly, the pivot arm being removably coupled to the frame assembly;operably coupling a drill bit to the pivot arm so the drill bit followsa predetermined path in fixed relation with respect to the frameassembly as the pivot arm is rotated; rotating the drill bit in fixedrelation to the frame assembly to form a first channel in a surface orsub-surface of the bone, bony structure or vertebrae that communicateswith the intervertebral disc space; detaching the pivot arm from theframe assembly; reattaching the pivot arm to the frame assembly; andforming a second channel adjacent to and connecting with the firstchannel.